Cibola's two channels - What's actually Happening?

[Bleaver]

I know Cibola is a single frequency machine.

However, the instruction manual has the following statement; "The discriminate circuit uses two different channels, then amplifies and filters them."

I take it the same information is being processed twice in different ways. Can anyone shed a little light on this and explain what is actually occuring?
Thanks

 

[JB(MS)]

Might be off on this, and probably am, but I assume the two channels Tesoro are referring to are what are more commonly referred to as filters. According to George Payne, a two filter detector actually has four filters, two high pass filters to eliminate the ground effect and two low pass filters to limit the noise that occurs when a high pass filter is used. It's pretty complicated and I don't understand much of it, but George said a signal from a target is made of two components that are referred to as the X and R components. The X and R components are applied to the filters to remove ground minerals, then the value of X and R are added together and the X value is divided by the results using the X / (X + R) computation and a circuit uses the result to determine the phase of the target and the detector gives a response that lets us know what conductance range the target is in. I'm paraphrasing what George said, and I may be a little off as I'm writing this from memory, but since he discovered the phase shift principle that allows discrimination, and designed the first circuits using it, I figure he knows what he's talking about even if I don't.